An on-board navigation system can be advantageous to a driver of an automobile when navigating streets in an unfamiliar area. Such systems are often found in rental cars and are becoming increasingly more available as options in new cars. An on-board navigation system may include a computer, a stored street map database, and various sensors to detect vehicle movement. The system is designed to compute a route to a selected destination and generate guidance instructions to guide the user along the computed route. The system may include a visual display device, such as a liquid crystal display (LCD), by which navigation information and other information are provided to the user. For example, the system might display a moving vehicle symbol on an image of a street map to indicate the movement of the vehicle through a given area. The system might also display symbolic or textual navigation instructions, such as a directional arrow to indicate the next turn, or the instruction, "Right turn on Innsbruck Drive." Visual navigation instructions may be accompanied by audible instructions generated as digitized or synthesized speech. The system generally includes some type of input device, such as push buttons, to allow the user to select a destination and perform various functions, such as changing the scale level of the map display. On-board automobile navigation systems having features such as those mentioned above are produced by Zexel USA Corporation, located in Sunnyvale, Calif.
One problem with many on-board navigation systems is that the manner of selecting the desired destination is inconvenient for some users. With one existing system, the driver pushes buttons to select a destination from a displayed list of possible destinations. The user first selects a city from a list of cities, then selects a street name from a list of street names, and then selects a street number. Some people, however, dislike having to manually input the destination. In some cases, the user may be in a hurry and may not wish to be delayed by having to input the destination. Further, certain people are apprehensive about using even relatively simple electronic devices; having to manually input a destination may tend to discourage such people from using a navigation system. Hence, it is desirable to provide an on-board automobile navigation system which simplifies the process of entering a desired destination for the user.
Another problem with many on-board navigation systems is that they tend to be expensive; on-board navigation systems in new cars are still generally among the highest-priced options. It is desirable, therefore, to reduce the overall cost of on-board navigation systems to make such systems more available to consumers. One significant factor in the cost of these systems is the visual display device and its associated hardware, which typically represent a large fraction of the cost of the entire system (approximately 30 percent in at least one existing system). It would advantageous, therefore, to reduce or eliminate costs associated with these components without sacrificing the essential functionality of the navigation system and without reducing the appeal of the system to consumers.
Thus, it is desirable to provide an on-board automobile navigation system which simplifies the process of entering a desired destination for the user. It is further desirable to reduce the cost of such a system while preserving the ability of the system to provide clear, step-by-step navigation instructions along a computed route to guide the user to a selected destination.